On Tue, Jan 8, 2013 at 1:09 PM, Kassen wrote:

On Tue, Jan 08, 2013 at 12:09:02PM -0600, Michael Heuer wrote:

...

I can't help but think that if I could figure out the notation of say Moorer's Figure 2.30 above to the point where I might translate into higher level ChucK delays, gains, and filters I could get lost for several hours making strange reverbs in Chuck instead. Can anyone help me get started?

Sure, for that diagram;

x(n) is your input signal

The "+" signs in the circles are points at which signals get summed

v(n) is the signal that enters the delay, it is a sum of x(n) and the delay's output.

The rectangular block is a delay of M samples length. When DSP people write "z-1" they are referring to the last sample (typically the last output of the system). Pronounce; "z minus 1". Why do they write it up high like it were taking the "-1th power"? I don't know. Maybe they just want to make it all hard to read to make themselves seem smart, maybe they just copy each other ;-) y(n) is the output signal (which we hear).

b0 is the amount of feedforward; basically the amount of v(n) that ends up in the output. "b" indices are feedforward, b0 means the signal 0 samples ago.

-aM is the amount of (negative) feedback from the delayed signal. a indices are as you might guess feedback, this is the output signal M samples ago. Note that our filters also have member functions like .a1(), .b0(), etc. Those are like this.

ok, me being niave: Gain x => Gain v => Gain b => Gain y; in => Delay z => Gain postZ => y; postZ => Gain a => v; adc => x; y => dac; 0.25 => b.gain; -0.25 = a.gain; ?

[E]xperiments with feedback can and will lead to loud accidents, prepare for that. Of course they are also a LOT of fun, be careful, not discouraged :-)

Yep, that is what I'm going for. Thank you, Kas. michael

On Tue, Jan 08, 2013 at 01:54:27PM -0600, Michael Heuer wrote:

ok, me being niave:

That's totally ok, all of this is quite naive, as far as reverbs go, but it's also cheap fun :-). The corrected version of your second mail looked fine to me. The article suggest using a few of these. If you are at all interested in doing a ChuGin this might be a good test case?

Yep, that is what I'm going for. Thank you, Kas.

You're welcome. If you come up with something good consider sharing. Somewhat off-topic-ish; https://en.wikipedia.org/wiki/Hagia_Sophia If you ever have the chance visit that one, it'll ruin "cathedral" presets for you. Ok, that does not sound like a recommendation, I admit, but it blew my mind, reverb-wise. Back on topic; those popular Lexicon units tend to "cheat" by including bit of chorus effect, you might want to try that too. Yours, Kas.